Pump



June 12. 1928.

1,673,260 c. R. MEs-roN r-:T AL

PUMP

Filed Marca 11, 192e 3 sheets-sheet 1 im w , BY l mmm/( f ATTO NEYS June12, 192s. 1,673,260

- Cv. R. MESTON El AL PUMP Filed March l1, 1926 3 Sheets-.Sheet 3INVENTORS fqf'lr Mem!" /Zlcc/f Meat Patented June l2, 1928.

UNITED STATESl PATENT OFFICE.

CHARLES B.. MESTON AND' ALECK W. MESTON, OF YONKERS, NEW YORK, ASSIGNORSTO TBIE STACOLD CORPORATION, OF NEW YORK, N. Y., A. CORPORATION 0F NEWYORK.

PUMP.

Application led latch 11, 1926. Serial No. 93,820.

This invention relates to pumps and particularly to air or gas pumpssuch as are used in refrigeratingapparatus.

The invention has been particularly worked out in connection with pumpsutilizing intermeshing gears for pumping air or gas. With this type'ofpump, it 1s essential that the gear teeth fully intermesh and that therebe no leakage of air around the teeth in the casingnat the outlet sideof the pump or leakage from the casing around the pump shaft. When thepump is used. as a high pressure pump, it is very diiiicult to preventleakage of air or gas from the discharge side of the pump. Furthermore,the high pressure acting on the pump elements tends to exert a thrustthereon and cause wear of the gears and contacting parts of tbe pump.

The invention has for its salient object to provide a pump so made as toobtain extreme accuracy in construction at a minimum manufacturing cost.

Another object of the invention is to provide a pump of the characterdescribed so constructed that there will be practically no leakage atthe outlet or high pressure side of the pump.

Another object of the invention is to provide a structure ofthecharacter described in which the pressure is equalized at the ends -ofthe gear elements so that `no appreciable thrust is exerted on thegears.

Another object of the invention is to provlde a pump of the characterdescribed in f which the drive shaft is so connected to the pump that noleakage from the casing will occur around the shaft.

. Further objects of the invention will appear from the followingspecification taken in connection with the drawings, lwhich form a partof this application, and in which Fig. 1 is a sectional elevation of apump constructed in accordance with theinvention;

Figs. 2 and 3 are transverse sectional elevations taken substantially onlines 2 2 and 3 3 of Fig. 11;.

Fig. 4 ,is a. sectional elevation taken substantially on line 4-4 ofFig. 1;

Fig. 5 is a sectional elevation taken mounting the gears and shaftbearings in straight bores, the bearings, bushings and gears will bepositioned in accurate alinement thus providing extreme accuracy at akminimum of expense in manufacturing.

If desired, to provide for taking upavear or other contingencies and tofurther insure an accurate fit, the plugs or bearing boxes have theircenters disposed very slightly eccentric to the center of the boresinthe casing in such a manner that the pump gearing will accurately fitthe casing at the discharge side of the pump but will clear thecasing atthe inlet side of the pump. This prevent-s leakage at the high pressureside of the pump and prevent-s the gears -from dragging or rubbing onthe casingat the intake side of the pump in case the gear shafts becomeworn or the bearings permit the gears to get out of alinement.

Means is also provided in the pump Afor eliminating end thrust and alsofor preventing lleakageof the air or gas from the pump casing around thedrive shaft and for preventing air vfrom leaking into the casing. Thisis accomplished in one form of the invention by providing a drive shaftwith a longitudinal recess at one end for receiving the gear. shaft. Therecessed end of the drive shaft is iianged and the flange engages a'spring ressed collar, the s ring being enclosed wit in an expansible rancontractible metallic casing. The s ring presses ythe flange intoengagement wit the collar and also presses the collar against a wall ofthe casing. The drive shaft is splined or keyed to the gear shaft. Inanother embodiment the drive shaft is splined or 4otherwise connected todrive one of the gears and is extended out through the casing end. 'Aflange on the shaft engages a collar asin the Erst form described andprevents leakage. VBy means of this construction the gear shaft floatsin its bearing and end thrust is 'largely eliminated.

Invthe form of the invention illustrated, sealing liquid is conducted tothe ends of the gears thus equalizing the pressure at the ends of eachlgear and a lubricant separate and distinct from the sealing liquid isused for lubricating the bearings.

Further details of the invention will appear from the followingdescription.

The pump casing consists of a body` portion 10 and end plates 11 and 12.The body portion ispreferably cast in a solid block and is boredlongitudinally to-form straight bores 15 and 16. (See Fig.'3.) The-bores15` and 16 as illustrated, consist of overlapping cylindrical opzeningswhich intersect in a common plane 1 There is positioned at each endpfeach A bore a bearing box or plug 20 and 1n these bearing boxes orbearing plugs are mounted ball bearings 21. The bearing boxes or plugs20. have substantially cylindrical outer surfaces but are formed withflat sides 22 adapted to be positioned in alinement with the commonplane 17. v A

The pumping'elements consist of a pair of intermeshing gears 25 and 26,herringbone gears being illustrated. The gear 25 1s mounted on aI shaft27 and the gear 26 is mounted on a shaft 28, the shafts 27 andV 28 beingmounted in the bearings 21v carried by the plugs 20..,VV

The straight bores thus receive the gears, shaftsand shaft bearings andbecause of this construction the elements specified can be accuratelyalined.

As shown in Figs. 5 and 6, the bores 15 and 16 intersect in a knife edge30 at the high. pressure or discharge sdeof the pump and 1t is veryessentialthat the Vgear teeth 31 and 32 of the gears 25 and `26accurately lit the casing at this knife edge so asto prevent escape ofthe high pressure air or gas.

This' is accomplished by locating the plugs,V or bearing boxes 20, thegears, andgearV shafts in the straight bores 15 and 16.

It has been found advantageous to 'compensate for wear and to furtherinsure an accurate t of thel pump elements in the bores by locatingth'ecenters of the plugs vor bearin boxes 20 slightly eccentricto thecenters o the bores 15 and 16. Such a structure is shown in Figs. 5 and6, wherein the centers of the plugs are .located at a: and the centersof the bores are located at y. The point a: is located on 'a linedisposed' substantially 45 from the .line y-'y connecting the centers ofthe bores. By so positioning the centers `of the bearing boxes or plugs,it will be clear that the gear teeth 31 and `32`will'bepositioned infull intermeshing relation with reference to each vother and these teethwill also accurately through aconduit 40 and opening 41 formed in thecasing. The opening 41 communicates at its inner end with a recess 42formed in the casing body opposite the knife edge l30.

The air or gas or -other substance being pumped leaves the casing bodythrough openings 45 and 46 formed in the plugs 20 and communicating withdischarge conduits'.

47 and 48. l

In the form of the invention shown in Fig. 1, the drive shaft of thepump is s hown at 50 and is provided with a longitudinal recess 51. Theshaft 5() has a fiange 52 formed on the end of the recessed portionthereof, the iiange being adapted to seat against a portion A 53 of thecasing end plate 12.

The end plate 12 has formed thereon a boss 54 into which the shaft 50extends and the' open end of the boss is closed by :a cap 55. A 4spring56 seats at one endagainst the cap 55 and at its opposite end against acollar 57 which carries a packing 58 vadapted to engage the flange 52. Aiex'ible'bellows is secured atone end to the collar 57 and.

at -its other end to a washer 59 which is securedl by the cap 55 againstthe outer end of the boss 54.

From the showing in Fig. 1 it will be seenV end Yplate 12, thus tending.to preventl the'4 escape vof any of the sealing liquid from the Y7asimilar .shaft seal vis illus- AYtr'ated but infthis embodiment a an'ge52^ is formed on the shaft 27f and this shaft is extended through theend plate and cap 55. The gear 25 is splined to or mounted on squaredportion 27B of the shaft and is slidable thereon but rotatabletherewith. .The flange 52A bears against collar or^washer 57 as beforeand the spring 56, washer 59, andbellows between washer 69 and collar57A operate as in Fig. 1.

The body 10of the pump casing is mounted on a base plate 60 which inturn is mounted on and forms. the top for a cooling reservoir or chamber61. Thecasingbody 10 has formed in its outer surface a pair trated, theliquid used for sealing the pump elements enters the cooling reservoiror chamber 61 through a conduit 70 and passes around a coil 71 disposedin the chamber 61 and through a conduit 72 to a strainer 73.

From the strainer 7 3 the sealing liquid passes through an opening 74 inthe strainer casing into a conduit 75 which leads to annular recesses orgrooves 76 formed on the l inner surface of the plugs 20 disposed at theends of the gear 26. (See Fig. l.) Also, on referring to Fig. 2, it willhe seen that the sealing liquid passes through a conduit 77 to a conduit78 which is connected bv conduits 79 and 80 to the grooves 76 formed 1nthe plugs 20 disposed at the ends of the gear 25. v

The conduit 77 also communicates with a conduit 81 which in turnconducts sealing llquld through minute passages 82 to the gear teeth,thus sealing the contactbetween the teeth and the casing at the highpressure side of thel pump.

Conduit 79 also conducts sealing liquid tp a. conduit 83 which in turnconducts the liquid to the outwardlv extending portion of the shaft 27and the liquid thus conducted w1ll seal the contact between the collar52 and portion 53 of the end plate 12.

The recess or chamber in the boss 54, around the bellows. is filled withoil at all times, due to the oil or sealing liquid that is forced outbetween flange 52 and wall 53 and to insure a supply of lubricant or oilin the chamber when the pump is started an opening 84 is provided in theboss. A plug 85 tightly closes this opening when sealing liquid is notbeing supplied to the chamber.

When the pump shuts down, unless all the valves are tight, there may bea vacuum in thepump and this tends to draw air into the pump. Theadmission of air is very deleterious to the pump especially wheresulphur dioxide is the refrigerant and so it is very important toprevent air'frqm entering. This important functi'difis performed by thebellows and by sealing liquid in the chamber in boss 54, which seals thecontact between washer 57 and ange 5255erA 52A.

In the form of the inventionl illustrated in the drawings, the sealingliquid is notl usedjn to lubricate the bearings but a. separate anddistinct lubricant is used. l It will be noted that the en'd plates 11and 12 are provided' It will be understood that the sealing liquidpasses from the pump with the air or gas pumped, is extracted from thegas in a separator and returns to the coil 7l through pipe and underpressure of the gas or air delivered by the pump.

From the foregoing specification is will be seen that a pump'structurehas been provided in which the gear elements will accurately fit thecasing and prevent escape of air or gas and loss of pressure at thedischarge side of the pump and in which the pumping elements will befree from or clear of the casing at the intake side thereof.Furthermore, by reason of the fact that the sealing Huid 'passes to bothends of the pump shafts, and by reason' of the form ofshaft seal andelimination of stuffing boxes, the pressure is equalized and end thrustis minimized.. The pump drive shaft has been so connected to the gearingthat leakage from the casing around the shaft is eliminated orpractically eliminated andthe pressure within the casing tends toprevent escape of air or gas from the casing.

Although certain specific embodiments of the invention have beenparticularly shown and described, it will be understood that theinvention is capable of modification and that changes in theconstruction and 'in the arrangement of the variouscooperating parts maybe made Without departing from the spirit or scope ofthe invention asexpressed in the following claims.

What we claim is:

1. In combination, a casing, a shaft. mounted in' said casing` andextending through the wall thereof, a drive shaft 'telescoping with saidshaft extens1on keyed thereto and slidable relativethereto, a flangeformed on the outer telescoping member, a collar surrounding said memberand engaging said flange, resilient means pressing said collar againstsaid flange and an expansible and a eontraetible sheath surrounding saidresilient means and secured to the collar and casing for preventingsealing liquid from leaking thereon.

2. In combination, a easing, a shaft mounted therein and extendingoutwardly through one wall thereof, a shaft having a recessed endslidably receiving the extended end of said first shaftand having aflange on the end thereof, a ,boss on said casing s urrounding saidshafts and fiange and havlng an opening forming a pocket, a capon theouter end of said boss, the' shaft -ange be-A ing disposed in engagementwith the wall of the casing, a Washer surrounding said shafts andengagmg said flange and a spring mounted between said cap-and saidwasher for pressing the Washer against the flange and the ange againstthe casing wall and a iexible metallic sheath secured between said capand said Washer and surrounding said 'spring for preventing sealing uidfrom escaping.

In witness whereof, I have hereunto set In Witness whereof, I havehereunto set my hand this 8th day of March, 1926. ALECK W. MES'ION.

